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Diffstat (limited to 'activemodel/README')
| -rw-r--r-- | activemodel/README | 189 |
1 files changed, 175 insertions, 14 deletions
diff --git a/activemodel/README b/activemodel/README index 7c9c754a8e..cf103b8d6d 100644 --- a/activemodel/README +++ b/activemodel/README @@ -12,32 +12,55 @@ Active Model provides a known set of interfaces that your objects can implement to then present a common interface to the Action Pack helpers. You can include functionality from the following modules: -* Adding callbacks to your class +* Adding attribute magic to your objects - class MyClass - extend ActiveModel::Callbacks - define_model_callbacks :create + Add prefixes and suffixes to defined attribute methods... + + class Person + include ActiveModel::AttributeMethods + + attribute_method_prefix 'clear_' + define_attribute_methods [:name, :age] + + attr_accessor :name, :age + + def clear_attribute(attr) + send("#{attr}=", nil) + end + end + + ...gives you clear_name, clear_age. + + {Learn more}[link:classes/ActiveModel/AttributeMethods.html] + +* Adding callbacks to your objects - def create - _run_create_callbacks do - # Your create action methods here - end - end - end - - ...gives you before_create, around_create and after_create class methods that - wrap your create method. + class Person + extend ActiveModel::Callbacks + define_model_callbacks :create + + def create + _run_create_callbacks do + # Your create action methods here + end + end + end + + ...gives you before_create, around_create and after_create class methods that + wrap your create method. {Learn more}[link:classes/ActiveModel/CallBacks.html] * For classes that already look like an Active Record object - class MyClass + class Person include ActiveModel::Conversion end ...returns the class itself when sent :to_model + {Learn more}[link:classes/ActiveModel/Conversion.html] + * Tracking changes in your object Provides all the value tracking features implemented by ActiveRecord... @@ -55,3 +78,141 @@ functionality from the following modules: {Learn more}[link:classes/ActiveModel/Dirty.html] +* Adding +errors+ support to your object + + Provides the error messages to allow your object to interact with Action Pack + helpers seamlessly... + + class Person + + def initialize + @errors = ActiveModel::Errors.new(self) + end + + attr_accessor :name + attr_reader :errors + + def validate! + errors.add(:name, "can not be nil") if name == nil + end + + def ErrorsPerson.human_attribute_name(attr, options = {}) + "Name" + end + + end + + ... gives you... + + person.errors.full_messages + # => ["Name Can not be nil"] + person.errors.full_messages + # => ["Name Can not be nil"] + + {Learn more}[link:classes/ActiveModel/Errors.html] + +* Testing the compliance of your object + + Use ActiveModel::Lint to test the compliance of your object to the + basic ActiveModel API... + + {Learn more}[link:classes/ActiveModel/Lint/Tests.html] + +* Providing a human face to your object + + ActiveModel::Naming provides your model with the model_name convention + and a human_name attribute... + + class NamedPerson + extend ActiveModel::Naming + end + + ...gives you... + + NamedPerson.model_name #=> "NamedPerson" + NamedPerson.model_name.human #=> "Named person" + + {Learn more}[link:classes/ActiveModel/Naming.html] + +* Adding observer support to your objects + + ActiveModel::Observers allows your object to implement the Observer + pattern in a Rails App and take advantage of all the standard observer + functions. + + {Learn more}[link:classes/ActiveModel/Observer.html] + +* Making your object serializable + + ActiveModel::Serialization provides a standard interface for your object + to provide to_json or to_xml serialization... + + s = SerialPerson.new + s.serializable_hash # => {"name"=>nil} + s.to_json # => "{\"name\":null}" + s.to_xml # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person... + + {Learn more}[link:classes/ActiveModel/Serialization.html] + + +* Turning your object into a finite State Machine + + ActiveModel::StateMachine provides a clean way to include all the methods + you need to transform your object into a finite State Machine... + + light = TrafficLight.new + light.current_state #=> :red + light.change_color! #=> true + light.current_state #=> :green + + {Learn more}[link:classes/ActiveModel/StateMachine.html] + +* Integrating with Rail's internationalization (i18n) handling through + ActiveModel::Translations... + + class Person + extend ActiveModel::Translation + end + + {Learn more}[link:classes/ActiveModel/Translation.html] + +* Providing a full Validation stack for your objects... + + class Person + include ActiveModel::Validations + + attr_accessor :first_name, :last_name + + validates_each :first_name, :last_name do |record, attr, value| + record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z + end + end + + person = Person.new(:first_name => 'zoolander') + person.valid? #=> false + + {Learn more}[link:classes/ActiveModel/Validations.html] + +* Make custom validators + + class Person + include ActiveModel::Validations + validates_with HasNameValidator + attr_accessor :name + end + + class HasNameValidator < ActiveModel::Validator + def validate(record) + record.errors[:name] = "must exist" if record.name.blank? + end + end + + p = ValidatorPerson.new + p.valid? #=> false + p.errors.full_messages #=> ["Name must exist"] + p.name = "Bob" + p.valid? #=> true + + {Learn more}[link:classes/ActiveModel/Validator.html] + +
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